The correct order of cell types from least differentiated to most differentiated is:
totipotent stem cells → pluripotent stem cells → multipotent stem cells → neuron
Here's the reasoning:
- Totipotent stem cells can develop into any type of cell in the body, as well as the extraembryonic (placental) tissues.
- Pluripotent stem cells can develop into almost any cell type but cannot form extraembryonic tissues.
- Multipotent stem cells are more specialized and can only develop into a limited range of cell types related to a specific tissue or organ.
- Neurons are fully differentiated cell types specialized for a specific function in the nervous system.
Thus, the correct choice is: totipotent stem cells → pluripotent stem cells → multipotent stem cells → neuron.